It is known to use rapeseed to obtain oil by pressing. It is further known from EP 1 074 605 B1 to dehull the rape grains before their pressing and to separate the kernel fractions and the husk fractions from one another. Rape oil is then obtained from the light, yellow kernel fractions by pressing which then likewise has a yellowish color pleasing to the customer.
There is the problem on such a pressing that only around a third of the pressed material accrues as high-quality oil and approximately two-thirds remain as oil cake having a solid and oil content.
It is therefore furthermore known in turn to supply substantially blackish gray husk fractions to the remaining oil cake and to subject the mixture thus obtained to a further pressing in order thereby to increase the oil fraction obtained overall.
The oil cake having a solid content still remaining after this further pressing is of an overall grayish green color due to the reintroduced husk fractions having anti-nutritional ingredients and is for this reason alone only used as animal feed or as an admixture.